Biomechanical testing of hip protectors following the Canadian Standards Association express document

Summary A variety of hip protectors are available, but it is not clear which is the most effective and there is no standard test to evaluate their performance. This is the first study that uses a standard mechanical test on hip protectors. Some protectors perform well but others are almost ineffective, providing little to no protection to the wearer during a fall. Introduction Each year, over 70,000 patients are admitted to hospital in the UK with hip fractures. There are a variety of commercial hip protectors currently available. However, it is not explicitly clear which is the most effective with regard to maximum force attenuation, whilst still being both comfortable for the user and providing reasonable force reduction if misplaced from the intended position. The numerous test methods reported in the literature have given conflicting results, making objective comparison difficult for users, researchers, and manufacturers alike. The Canadian Standards Association (CSA) has therefore published an express document (EXP-08-17) with a draft standard test method. This paper presents initial results for a range of hip protectors. Methods Eighteen commercially available hip protectors were tested according to EXP-08-17. Each hip protector was impacted five times in correct anatomical alignment over the greater trochanter and once at 50 mm displacements in the anterior, posterior, and lateral directions. Results Considerable differences were identified between individual hip protectors in their ability to reduce impact forces on the femur (between 3% and 36% reduction in peak force). The performance was reduced when misplaced in many cases (maximum reduction only 20%). Conclusions This is the first study that uses a standard mechanical test on hip protectors. Previous studies have used a variety of methods, making it difficult to interpret results. We hope that these results using a standard test method will facilitate the effective comparison of results, as well as providing useful data for clinicians, users, and purchasers

Book Reviews

State Taxation of Interstate Commerce By Paul J. Hartman Buffalo: Dennis & Co., 1953. Pp. xi, 323. $7.50 reviewer: James Clarence Evans ================================================ Church, State and Freedom By Leo Pfeffer Boston: The BeaconPress, 1953. Pp. xvi, 605.$10.00 reviewer: Samuel Enoch Stump

Catalytic reforming of biogas using nickel based perovskite materials

The utilisation of biogas as an energy source or as a feed stock for the chemical industry would help to lower the present wasteful and environmentally unfriendly venting of greenhouse gases to the atmosphere. One obstacle to this becoming a reality include finding a catalyst that is active towards carbon dioxide reforming of methane as well as resistance to carbon deposition and sulphur poisoning. As a potential alternative to supported nickel catalysts, a nickel doped perovskite has been produced via a hydrothermal synthesis method for reforming biogas. The selected perovskite, SrZrO3, was doped with 4 mol % nickel into the structure and shown to be phase pure by XRD. This material was rigorously tested catalytically using a range of biogas conditions. 4 mol% Ni doped SrZrO3 was shown to be resistant to carbon deposition under high temperature, methane rich biogas reforming conditions with no observable trend between the amount of carbon formed and the time on stream. This catalyst showed high activity and selective towards the formation of the desired products, an equimolar mixture of hydrogen and carbon monoxide. As naturally derived biogas is not a pure mixture of methane and carbon dioxide, studies into the effect that two of the other important components of biogas, water and sulphur containing compounds, were carried out. The perovskite material was seen to be stable towards continued dry reforming of methane irrespective of the inclusion of water, and at elevated reaction temperatures was able to convert the water into the required products of hydrogen and carbon monoxide. The effect of hydrogen sulphide was studied and the perovskite material was seen to be susceptible to sulphur poisoning. However the extent and the recovery from this type of deactivation was an improvement on that seen by Ni/YSZ and 5% ceria doped Ni/YS

Euler buckling in red blood cells: An optically driven biological micromotor

We investigate the physics of an optically-driven micromotor of biological origin. A single, live red blood cell, when placed in an optical trap folds into a rod-like shape. If the trapping laser beam is circularly polarized, the folded RBC rotates. A model based on the concept of buckling instabilities captures the folding phenomenon; the rotation of the cell is simply understood using the Poincar\`e sphere. Our model predicts that (i) at a critical intensity of the trapping beam the RBC shape undergoes large fluctuations and (ii) the torque is proportional to the intensity of the laser beam. These predictions have been tested experimentally. We suggest a possible mechanism for emergence of birefringent properties in the RBC in the folded state

Generation of cloned transgenic pigs rich in omega-3 fatty acids

Meat products are generally low in omega-3 (n-3) fatty acids, which are beneficial to human health. We describe the generation of cloned pigs that express a humanized Caenorhabditis elegans gene, fat-1, encoding an n-3 fatty acid desaturase. The hfat-1 transgenic pigs produce high levels of n-3 fatty acids from n-6 analogs, and their tissues have a significantly reduced ratio of n-6/n-3 fatty acids (P < 0.001). © 2006 Nature Publishing Group

Constellations of identity: place-ma(r)king beyond heritage

This paper will critically consider the different ways in which history and belonging have been treated in artworks situated in the Citadel development in Ayr on the West coast of Scotland. It will focus upon one artwork, Constellation by Stephen Hurrel, as an alternative to the more conventional landscapes of heritage which are adjacent, to examine the relationship between personal history and place history and argue the primacy of participatory process in the creation of place and any artwork therein. Through his artwork, Hurrel has attempted to adopt a material process through which place can be created performatively but, in part due to its non-representational form, proves problematic, aesthetically and longitudinally, in wholly engaging the community. The paper will suggest that through variants of ‘new genre public art’ such as this, personal and place histories can be actively re-created through the redevelopment of contemporary urban landscapes but also highlight the complexities and indeterminacies involved in the relationship between artwork, people and place